When transporting children in motorised or unmotorised vehicles, seats are used which have a belt securing system ensuring that the child does not fall out and is not thrown out of its seat particularly in the event of an accident.
For passenger cars, child seats of various sizes are offered which are positioned in a seat of the passenger car and secured therein. Thus, seats are available which fit children of different sizes and in which children are adequately braced against jolts which occur during a journey and at the same time are effectively protected by the belt system of the child seat. Child seats for passenger cars are for the most part based on an independent heavy construction. Very few of them can be used in other vehicles due to their weight and/or size.
With bike trailers, as an example of lightweight vehicles for transporting children, it is possible to achieve speeds of up to 50 km/h. The danger potential is considerable for a child transported in such a vehicle and becomes all the greater the less effectively the child is secured in the seat. This applies all the more if the child falls asleep and sinks down in the seat due to a lack of body tension, i.e. the child does not stay in a position which is optimum for safeguarding and support.
The seats of a large number of bike trailers and strollers for children are formed by one or more textile webs which are clamped into the frame construction of the vehicle. The size of the seats (or also of double seats for two-seater bike trailers or strollers) is predetermined in each case by the frame construction, i.e. is not variable. There is often no classification of bike trailers according to age group or size of child; they are generally intended for children up to an age of approximately five. Although the seats in bike trailers are designed for children, they are often too large particularly for transporting small children, so that the transport of children that are smaller such as infants and toddlers, for example with ages of six months to two years, in bike trailers can sometimes be a problem. However, most suitably sized child seats for passenger cars cannot be reasonably used in a bike trailer, because the seats of bike trailers are not suitable for accommodating such child seats. The same applies accordingly to strollers.
The size of a seat in an airplane cannot be readily configured to be variable and passenger car child seats are generally unsuitable for use in airplane seats. Likewise, therefore, airplane seats may sometimes leave children not braced adequately.